Is there a link between hyperuricemia, morning blood pressure surge, and non-dipping blood pressure pattern in metabolic syndrome patients?

BACKGROUND Hypertensive patients usually have a blunted nocturnal decrease, or even increase, in blood pressure during sleep. There is also a tendency for increased occurrence of cardiovascular events between 6 and 12 am due to increased morning blood pressure surge (MBPS). Co-occurrence of metabolic syndrome (MetS) and hypertension is also a common problem. Hyperuricemia might trigger the development of hypertension, chronic renal failure, and insulin resistance. In this study, we aimed to determine whether there is a relationship between hyperuricemia, MetS, nocturnal blood pressure changes, and MBPS. METHOD A total of 81 newly diagnosed hypertensive MetS patients were included in this study. Ambulatory blood pressure monitoring of patients was done and patients' height, weight, and waist and hip circumferences were recorded. Fasting blood glucose (FBG), lipid profile, creatinine, potassium, uric acid, hematocrit levels were studied. RESULTS Non-dipper (ie, those whose blood pressure did not drop overnight) patients had higher waist-hip ratios (WHR) (P = 0.003), uric acid (P = 0.0001), FBG (P = 0.001), total and low-density lipoprotein cholesterol levels (P = 0.0001). Risk analysis revealed that hyperuricemia was a risk factor for non-dipping pattern (P < 0.0001, odds ratio = 8.1, 95% confidence interval = 1.9-33.7). Patients in the highest quadrant for uric acid levels had higher FBG (P = 0.001), low-density lipoprotein cholesterol (P = 0.017), WHR (P = 0.01), MBPS (P = 0.003), and night diastolic blood pressure compared with lowest quadrant patients (P = 0.013). Uric acid levels were also positively correlated with night ambulatory blood pressure (ABP) (r = 0.268, P =0.05), night diastolic blood pressure (r =0.3, P =0.05), and MBPS (r =0.3, P =0.05). CONCLUSION Evaluation of hypertensive patients should also include an assessment of uric acid level and anthropometric measurements such as abdominal obesity. Hyperuricemia seems to be closely related to undesired blood pressure patterns and this may signal to the clinician that an appropriate therapeutic approach is required.